Comment by m_kos
1. I find Tim's work always so impressive and humbling. Compared to software, hardware projects seem infinitely more complex.
2. Speaking of knobs, I am writing a toy software synth for smartphones. Are there any design guidelines for mobile UI for audio? Knobs are hard to use and sliders take up a lot of space with only a little more precision. I experimented with curved sliders (inverted parabola or sine), but they are confusing since height doesn't really encode anything and the curvature is there only to make the slider longer. I didn't find any design systems focused on audio components.
Knobs shouldn't be hard to use - hold down the knob that needs the adjustment and then drag in either of two directions to set the value. Maybe have a pop-up over the knob that displays the value as it's in use.